The most mature and common of the network applications is Ethernet. In the past 25 years, despite stiff competition from the latest network architectures, Ethernet has flourished. In the last 10 years alone, Ethernet has been updated to support speeds of 100 Mbps, 1 Gbps (approximately 1000 Mbps), and 10 Gbps; Currently, 40 and 100 Gigabit Ethernet are being standardized on the IEEE 802.3b committee. Forty-100 Gigabit Ethernet will be deployed over fiber optics for 100 meters or more, and research is being done to make it available via UTP for distances of up to 10 meters.
Ethernet has evolved to the point that it can be used in several different cabling systems.
10 Mbps Ethernet systems
10Base-5: “Standard Ethernet Cable”
The first version of Ethernet ran on a rigid coaxial cable that was called a standard Ethernet cable, but was more commonly called a thick network. Although the thick network was difficult to work with (because it was not very flexible and difficult to install and connect nodes), it was reliable and had a usable cable length of 500 meters. 10Base-5 systems can still be found in older installations, generally used as a backbone cable, but there is virtually no reason to install a new 10Base-5 system today. >> 10Base-T Ethernet
10Base-T: 10Mbps Ethernet over unshielded twisted pair cable. The maximum cable length (network device to network card) is 100 meters. 10Base-T (T stands for twisted pair) Ethernet is less common today and has been outperformed by 100Base-T. Even though 10Base-T uses only two pairs of a four-pair cable, all eight pins must be connected correctly in anticipation of future updates or other network architectures.
Specifications for using Ethernet over fiber optic cables existed in the early 1980s. Originally, fiber optic cable was simply used to connect repeaters whose spacing exceeded the distance limitations of thick network cable. The original specification was called Fiber Optic Inter-Repeater
Link (FOIRL), which describes the union of two repeaters with a fiber optic cable of up to 1,000 meters (3,280´) in length. The cost of fiber optic repeaters and fiber optic cabling was greatly reduced during the 1980s, and connecting individual computers directly to the hub through fiber optic cable became more common. Originally, the FOIRL specification was not designed with individual computers in mind, so the IEEE developed a series of fiber optic media specifications. These specifications are collectively known as 10Base-F. Today, it is rare to use fiber optics at these slow speeds. For historical purposes, the individual specifications for (and the methods to implement) 10Base-F Ethernet include the following:
10Base-2 is still a great way to connect a small number of computers in a small physical area, such as a home office, classroom, or
laboratory. The 10Base-2 Ethernet uses thin coaxial (RG-58 / U or RG-58 A / U) to connect computers to each other. This thin coaxial cable is also called a thinnet.
100 Mbps Ethernet systems
The 100Mbps version of 802.3 Ethernet specifies several different cabling methods for a Fast Ethernet system, including 100Base-TX, 100Base-T4, and 100Base-FX.
The 100Base-TX specification uses ANSI developed physical media specifications that were originally defined for FDDI (ANSI X3T9.5 specification) and adapted for twisted pair cabling. The 100Base-TX requires Category 5e or better cabling, but uses only two of the four pairs. The eight position modular jack (RJ-45) uses the same pin numbers as 10Base-T Ethernet.
The 100Base-T4 specification was developed as part of the 100Base-T specification so that existing Category 3 compliant systems could also support Fast Ethernet. Designers achieve 100 Mbps throughput on Category 3 cabling by using all four wire pairs; 100Base-T4 requires
a minimum of Category 3 cable. The requirement can ease the migration path to 100Mbps technology.
Like its copper cousin 100Base-TX, 100Base-FX uses an ANSI-developed physical media specification for FDDI. The 100Base-FX specification was developed to allow the use of 100Mbps Ethernet over a fiber optic cable. Although the cabling plant is connected in a star topology, 100Base-FX is
A bus architecture.
Gigabit Ethernet (1000Mbps)
1000Mbps Ethernet was only compatible with fiber optic cable. The IEEE 802.3z specification included support for three physical media (PHY) options, each designed to support different distances and types of communications:
Aimed at internal building backbones and horizontal cabling applications such as workstations and other network nodes, 1000Base-SX is designed to work with multimode fiber optic cable at the 850nm wavelength.
Designed to support backbone cabling like campus backbones between buildings, 1000Base-LX is for 1310nm single-mode fiber optic cable, although multimode fiber can be used for short backbones between buildings and intra-building cabling applications.
Designed to support interconnection of equipment groups, this specification uses 150 ohm STP cabling similar to IBM Type 1 cabling over distances of no more than 25 meters. When cabling Gigabit Ethernet with fiber, you must follow ANSI / TIA-568-C standards for 62.5 / 125 micron or 50/125 micron multimode fiber for horizontal cabling and 8.3 / 125 micron singlemode fiber for backbone cabling. See Table 6 of Annex D in ANSI / TIA-568-C.0.
Gigabit Ethernet over Category 5 or higher UTP cable where the installation has passed the performance tests specified by ANSI / TIA / EIA-568-B. The maximum distance is 100 meters from the equipment outlet to the switch. The IEEE designed 1000Base-T with the intention of supporting Gigabit Ethernet on the desktop. One of the main design objectives was to support the existing Category 5 cabling base.
10 Gigabit Ethernet (10,000Mbps)
The IEEE approved the first Gigabit Ethernet specification in June 2002: IEEE 802.3ae. Defines an Ethernet version with a nominal data rate of 10 Gbit / s. Over the years, the following 10 GbE-related 802.3 standards have been published: 802.3ae-2002 (Fiber Physical Media Dependent Devices [PMD] -SR, -LR, -ER, and -LX4), 802.3ak- 2004 (-CX4 InfiniBand dual-axis copper cable), 802.3an-2006 (10GBASE-T copper twisted pair), 802.3ap-2007 (-KR y-KX4 PMDs copper backplane), and 802.3aq-2006 (- LRM over legacy multimode fiber) LRM PMD with electronic dispersion compensation [EDC]). Amendments 802.3ae-2002 and 802.3ak-2004 were consolidated in the IEEE 802.3-2005 standard. IEEE 802.3-2005 and the other amendments have been consolidated into the IEEE 802.3-2008 standard. In the on-premises environment, 10 Gigabit Ethernet is primarily used in data center storage servers, high-performance servers, and, in some cases, in internal building backbones. It can be used to connect directly to the desktop.
10GBASE-SR (short range)
10GBASE-SR (short range) uses 850nm VCSEL lasers on multimode fibers. 62.5 / 125 micron (OM1) and 50/125 micron (OM2) low bandwidth multimode fiber supports limited distances of 33–82 meters. To support 300 meters, the fiber optic industry developed a 50/125 micron higher fiber bandwidth version optimized for use at 850nm.
10GBASE-LR (long range)
10GBASE-LR (Long Range) uses 1310nm lasers to transmit over single-mode fiber up to 10km. Fabry-Pérot lasers are commonly used in 10GBASE-LR optical modules. Fabry-Pérot lasers are more expensive than 850nm VCSELs because they require precision and tolerances to target very small single-mode core diameters (8.3 microns). 10GBASE-LR ports are typically used for long distance communications.
10GBASE-LX4 uses Coarse Wavelength Division Multiplexing (WDM) to support 300 meters over standard low bandwidth 62.5 / 125 micron (OM1) and 50/125 micron (OM2) multimode fiber cabling. This is accomplished through the use of four separate laser sources operating at 3,125 Gbps in the 1300 nm range at single wavelengths. This standard also supports 10 kilometers on single-mode fiber. 10GBASE-LX4 is used to support standard singlemode and multimode fiber with a single optical transceiver. When used with standard multimode fiber, an expensive mode conditioning patch is required. The mode conditioning connection cable is a short length of single-mode fiber that connects to the multimode in such a way that it moves the beam away from the central defect in the inherited multimode fiber. Because 10GBASE-LX4 uses four lasers, it is more expensive and larger than 10GBASE-LR. To decrease the footprint of 10GBASE-LX4, in 2006 a new module, 10GBASE-LRM, was standardized.
10GBASE-LRM (long-range multimode) supports distances of up to 220 meters in standard, low bandwidth of 62.5 / 125 microns (OM1) and 50/125 microns (OM2) using a 1310nm laser. Costly conditioning patch cord may also be required over standard fibers. 10GBASE-LRM doesn’t go as far as the old 10GBASE-LX4 standard. However, 10GBASE-LRM modules are expected to be of lower cost and lower power consumption than 10GBASE-LX4 modules. (It will still be more expensive than 10GBASE-SR).
10GBASE-T supports 10 Gbps over Category 6A or Category 7 shielded UTP cables (per ISO / IEC 11801Ed. 2) twisted pair over 100 meter distances. Category 5e supports much lower distances due to its limited bandwidth. Special care should be taken when installing Category 6A cables to minimize external interference to signal performance.
40 and 100 Gigabit Ethernet
The IEEE 802.3ba committee is standardizing 40 and 100 Gigabit Ethernet. This will be deployed on OM3 50/125 multimode fiber optics for 100–200 meters, and research is underway to make it available via UTP for distances up to 10 meters. This could be the speed point at which there is a mass conversion of copper to fiber based systems.